Hydraulic Turbines with Exit Flow Direction Opposite to its Inlet Flow Direction

ABSTRACT

The invention introduces a hydraulic turbine that extract the energy from the hydraulic kinetic and potential energy through passing the fluid inside the turbine wheel. The fluid enters the wheel heart almost perpendicular to its axis in almost tangential direction, decelerates in diffusers and change direction to almost radial. The flow is them changes direction from almost perpendicular to the axis to axial, then to almost perpendicular to the axis again but in opposite direction to its entrance. To exit, the flow accelerates in nozzles and change its direction to exit almost tangential and opposite to its very beginning entrance. In brief the exit direction in the very end is opposite to the entrance in the very beginning the transfer from the inlet passage to the exit passage is also associated with almost hundred eighty degrees change in direction, and the flow is subjected to deceleration and acceleration. All of these actions produce torques in the same direction to be utilized to generate power.

TECHNICAL FIELD

The field is of hydraulic turbines where the turbine transforms the kinetic and potential hydraulic energy/power to a mechanical energy. The produced mechanical energy could be used to drive machines such as pumps or mills, or used to generate electric power.

BACKGROUND ART

The hydraulic turbines can be classified into two classes from the theory of operation point of View; reaction turbine and impulse turbine. Reaction turbines generate the power by changing the water pressure as it moves through the turbine, and thus the turbine must be submerged in the water flow. On the other hand, impulse turbine extracts the power by changing the momentum of a water jet. All turbines are utilizing the potential and/or kinetic energy of the flowing water to generate a mechanical energy which is furtherly used either to generate another kind of energy (electric energy for example) or directly drive a machine.

This is one of the oldest techniques used to generate power, and thus the art is very rich with too many kinds of turbines. Each turbine has its own sophistication and efficiency and suits a specific range of water head and flow rate. Still the hydraulic energy, as a green renewable energy is one of the most important sources to provide the ever increasing human demand with a clean power which utilization worldwide cannot be compared with its enormous availability.

DISCLOSURE OF INVENTION Technical Problem

Types and sizes of hydraulic turbines cover a wide range of applications, and most of them either very simple and utilize the very old technology, or require special technology which is not available in the developing societies. Dams are built worldwide to utilize the energy stored in huge amount of water with sufficient head, however still lot of small rivers and streams have a potential of not utilized power. Such sources can help the development of remote societies and help these societies to improve their life and increase their productivity. Even old turbines are under concern to utilize small streams for this purpose.

Solution to Problem

To maximize the extracted energy, the flowing water momentum is changed several times by passing inside the turbine wheel and the change is applied to its direction, acceleration and deceleration. The change occurs due to the conduits shape inside the turbine that guides the flow direction. Thus, the control is carried out by the conduits cross sections and directions. The generated profile should be optimized to maximize efficiency and avoid problem such as cavitation and separation. However, the turbine wheel should be able to adopt simple configurations that could be manufactured in societies under development to serve their needs. The generated energy can directly drives machines such as pumps or mills or used to generate electricity on grid or oft grid networks. The hydraulic energy is associated with water flow as a potential (head) or kinetic (velocity). FIG. 1 shows a typical example of hydraulic power plant. The reservoir (lake1) stores the water at high head (2). The water flows down to the power station through conduits (3) and moves (4) to the low level. The water flow enters the turbine wheel (7) mainly (not totally) horizontally (5, 6) and exits it also mainly horizontally (8).

FIG. 2 shows a cross section perpendicular to the turbine axis in the power plant at the turbine wheel entrance. The turbine may preferably be installed with its axis is vertical as shown in the figure, the selected alternative (but not the only possible) used throughout this description. The flow enters the wheel (7) either directly (5) from the conduit (3) and from all the directions (6) to reach the entire wheel circumference through the volute.

FIG. 3 shows a horizontal cross section in the turbine wheel (perpendicular cross section to its axis), where the fluid moves mostly horizontally in the passage between the outer circle (9) and the inner circle (10). The flowing cross section is formed by the blades (11) to enter through the small area (12) and leave through the large area (13), thus the flow decelerates through this diffuser passage. The entering and exiting areas are not determined only by the horizontal dimension, vertical dimension can also control the areas variation and then the mostly horizontal water flow will have some vertical velocity components.

The flow between the entering area (12) and the exiting are (13) is subject to changes in its momentum. First is changing its direction from almost tangential to close to radial direction, this change generates a counter clockwise (CCW) torque on the turbine wheel shaft. Perfect radial flow prevents the energy extraction action explained in the next figure. Second, the angular CCW deceleration results from flowing in the diffuser generate also a CCW torque. The flow moves to the exit passage through the inner conduit (14), which is displaced away from the center to form an arm to the generated flow force in order to generate the required turbine driving torque.

FIG. 4 shows a vertical cross section of the turbine wheel (7) with the entering flow (6) and the exiting flow (8). With respect to the wheel, the flow exits in the opposite direction to its entrance, has the associated change in the momentum will generate another CCW torque due to displacing the action of the associated flow force away from the wheel center as shown in FIG. 3.

FIG. 5 shows a horizontal cross section of the turbine wheel. The sequence of the flow is the reverse of the flow in the entrance passage and so is the direction, thus the generated torques will be also CCW torques. Both the flow direction change and acceleration in the nozzle shaped passage generate (CCW) torques.

BRIEF DESCRIPTION OF DRAWINGS

FIG. (1) shows a typical example of the main components of a hydraulic power plant.

FIG. (2) is a cross section perpendicular to its axis shows the turbine wheel perpendicular to its axis, its intake, and the conduits that feed it.

FIG. (3) is a cross section perpendicular to its axis of the turbine wheel perpendicular to its axis in its inflow passage. The figure demonstrates the mechanism of extracting power by utilizing the water momentum change though direction change and deceleration.

FIG. (4) shows to longitudinal cross section in the turbine wheel, where the water transfer from the inflow passage to the outflow passage. The flow direction change is shown and hence the extracted power due to the water momentum change is explained.

FIG. (5) is a cross section of the turbine wheel perpendicular to its axis at its outlet passage. The figure demonstrates the water momentum change and power extraction in this stage by utilizing the water momentum change though direction change and acceleration.

INDUSTRIAL APPLICABILITY

The hydraulic turbine can be utilized in a wide range of water head and flow availability. It suits the application of small heads and flow rates and hence it can be installed in large power plants to join the networks, or in off grid units to generate power in small scale for local societies. The small units can be used in electric, power generation or in driving directly machines. 

1. A hydraulic turbine, wheel characterized in that entrance and exit of fluid are in a plane perpendicular to the turbine axis whereas flow of fluid encompasses different levels and outlet flow runs in an opposite direction with respect to inlet flow. 2-11. (canceled)
 12. A hydraulic turbine according to claim 1, comprising several separate conduits.
 13. A hydraulic turbine according to claim 2, whereas each conduit is guided by two consecutive blades.
 14. A hydraulic turbine according to claim 1 comprises two series stages; an inlet stage and outlet stage.
 15. A hydraulic turbine according to claim 4, whereas both stages are built on the same axis of rotation.
 16. A hydraulic turbine according to claim 1 whereas all changes in the closed conduit flow occur within the wheel itself.
 17. A hydraulic turbine according to claim 1, whereas flow of fluid feed to inlet stage is almost tangential at entrance.
 18. A hydraulic turbine according to claim 7, whereas tangential flow is transferred to almost radial flow in the first stage as guided by blades.
 19. A hydraulic turbine according to claim 1, the hydraulic turbine wheel characterized inlet of fluid has a diffuser shape whereas outlet of fluid has a nozzle shape.
 20. A hydraulic turbine according to claim 9, whereas the fluid decelerates due to diffuser effect at inlet stage.
 21. A hydraulic turbine according to claim 9, whereas the fluid accelerates due to nozzle effect at outlet stage.
 22. A hydraulic turbine according to claim 8, whereas the radial flow leaving the inlet stage is transferred to axial flow before transferring back to almost radial flow, but in opposite direction while entering the outlet stage.
 23. A hydraulic turbine according to claim 1, a hydraulic turbine wheel characterized in that the exit conduits at the outlet stage divert the flow from the approximately radial direction to approximately tangential direction.
 24. A hydraulic turbine wheel according to claim 1, whereas part of the fluid momentum is transfused to the blades in each conduit and for each stage due to acceleration or deceleration or change in flow direction whether in same plane or in different planes.
 25. A hydraulic turbine wheel according to claim 14, whereas every momentum exchange produces a rotating torque in the same direction.
 26. A hydraulic turbine wheel according to claim 1, whereas the speed and levels of the wheel and feed can be adjusted according to varying stream stage. 